For users experiencing issues with HDMI Audio under Ubuntu 12.04, users
should try installing the “dkms-hda - 0.201211291615~precise1” package from
https://code.launchpad.net/~ubuntu-audio-dev/+archive/alsa-daily/+packages
and reboot; this will resolve the HDMI Audio issue found in Ubuntu 12.04

AMD Catalyst 12.11 CAP2 has just been released, and should be used in
conjunction with AMD Catalyst 12.11 Beta11

AMD Catalyst 12.11 Beta6 resolves the issue with engine and memory
clocks running too high when the GPU is idle. Clocks will now run at the
proper level when the GPU is idle. This issue was only observed with
specific displays and was observed in the AMD Catalyst 12.11Beta 4 and AMD
Catalyst 12.10 drivers.

Performance Highlights of the AMD Catalyst 12.11:

This driver introduces significant performance improvements for many games
across ALL 28nm AMD Radeon™ HD 7000 Series products: HD 7700, HD7800 and HD7900.